With the accelerated development of electric vehicles, interest in heating systems, which have not been an issue in typical automobiles, is rapidly increasing. Although typical automobiles have used an air blowing heater, an electric vehicle does not have a separate heating means and batteries of the electric vehicle suffer from efficiency reduction when external temperature falls down to about −10° C. in winter.
To overcome such a drawback, although a sheet heater based on energy transfer is applied to a battery in order to secure temperature uniformity, the sheet heater does not provide sufficient effects in warming the inside of automobiles in winter due to a limit of power consumption. Moreover, since the generally acceptable criteria of air temperature, at which passengers in an automobile feel comfortable, need to be determined and a method for efficiently achieving this temperature is required, there is a need for development of a heater for electric vehicles.